/Engine/Source/Runtime/RHI/Public/RHICommandList.h
FRHICommandCopyToStagingBuffer ( [FRHIBuffer](API\Runtime\RHI\FRHIBuffer) * InSourceBuffer, [FRHIStagingBuffer](API\Runtime\RHI\FRHIStagingBuffer) * InDestinationStagingBuffer, uint32 InOffset, uint32 InNumBytes )